Chair frame



FIG. 1 is a front perspective view of the chair frame;

FIG. 2 is a front view; and,

FIG. 3 is a left side view. The right side view is a mirror image of the left side view.

In FIGS. 1-3 the arms of the chair are shown in broken lines for illustrative purpose only and form no part of the claimed design. 

The ornamental design for a chair frame, as shown and described. 